Add support for Unix sockets

Patch originally by Dag-Erling Smørgrav for University of Oslo.

common/network/CMakeLists.txt

@@ -1,8 +1,14 @@
 include_directories(${CMAKE_SOURCE_DIR}/common)
 
-add_library(network STATIC
+set(NETWORK_SOURCES
   TcpSocket.cxx)
 
+if(NOT WIN32)
+  set(NETWORK_SOURCES ${NETWORK_SOURCES} UnixSocket.cxx)
+endif()
+
+add_library(network STATIC ${NETWORK_SOURCES})
+
 if(WIN32)
 	target_link_libraries(network ws2_32)
 endif()

common/network/UnixSocket.cxx

@@ -0,0 +1,250 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright (c) 2012 University of Oslo.  All Rights Reserved.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stddef.h>
+
+#include <network/UnixSocket.h>
+#include <rfb/LogWriter.h>
+
+using namespace network;
+using namespace rdr;
+
+static rfb::LogWriter vlog("UnixSocket");
+
+// -=- Socket initialisation
+static bool socketsInitialised = false;
+static void initSockets() {
+  if (socketsInitialised)
+    return;
+  signal(SIGPIPE, SIG_IGN);
+  socketsInitialised = true;
+}
+
+
+// -=- UnixSocket
+
+UnixSocket::UnixSocket(int sock, bool close)
+  : Socket(new FdInStream(sock), new FdOutStream(sock), true), closeFd(close)
+{
+}
+
+UnixSocket::UnixSocket(const char *path)
+  : closeFd(true)
+{
+  int sock, err, result;
+  sockaddr_un addr;
+  socklen_t salen;
+
+  if (strlen(path) >= sizeof(addr.sun_path))
+    throw SocketException("socket path is too long", ENAMETOOLONG);
+
+  // - Create a socket
+  initSockets();
+  sock = socket(AF_UNIX, SOCK_STREAM, 0);
+  if (sock == -1)
+    throw SocketException("unable to create socket", errno);
+
+  // - Attempt to connect
+  memset(&addr, 0, sizeof(addr));
+  addr.sun_family = AF_UNIX;
+  strcpy(addr.sun_path, path);
+  salen = sizeof(addr);
+  while ((result = connect(sock, (sockaddr *)&addr, salen)) == -1) {
+    err = errno;
+    close(sock);
+    break;
+  }
+
+  if (result == -1)
+    throw SocketException("unable connect to socket", err);
+
+  // - By default, close the socket on exec()
+  fcntl(sock, F_SETFD, FD_CLOEXEC);
+
+  // Create the input and output streams
+  instream = new FdInStream(sock);
+  outstream = new FdOutStream(sock);
+  ownStreams = true;
+}
+
+UnixSocket::~UnixSocket() {
+  if (closeFd)
+    close(getFd());
+}
+
+int UnixSocket::getMyPort() {
+  return 0;
+}
+
+char* UnixSocket::getPeerAddress() {
+  struct sockaddr_un addr;
+  socklen_t salen;
+
+  // AF_UNIX only has a single address (the server side).
+  // Unfortunately we don't know which end we are, so we'll have to
+  // test a bit.
+
+  salen = sizeof(addr);
+  if (getpeername(getFd(), (struct sockaddr *)&addr, &salen) != 0) {
+    vlog.error("unable to get peer name for socket");
+    return rfb::strDup("");
+  }
+
+  if (salen > offsetof(struct sockaddr_un, sun_path))
+    return rfb::strDup(addr.sun_path);
+
+  salen = sizeof(addr);
+  if (getsockname(getFd(), (struct sockaddr *)&addr, &salen) != 0) {
+    vlog.error("unable to get local name for socket");
+    return rfb::strDup("");
+  }
+
+  if (salen > offsetof(struct sockaddr_un, sun_path))
+    return rfb::strDup(addr.sun_path);
+
+  // socketpair() will create unnamed sockets
+
+  return rfb::strDup("(unnamed UNIX socket)");
+}
+
+int UnixSocket::getPeerPort() {
+  return 0;
+}
+
+char* UnixSocket::getPeerEndpoint() {
+  return getPeerAddress();
+}
+
+bool UnixSocket::sameMachine() {
+  return true;
+}
+
+void UnixSocket::shutdown()
+{
+  Socket::shutdown();
+  ::shutdown(getFd(), 2);
+}
+
+bool UnixSocket::cork(bool enable)
+{
+  return true;
+}
+
+UnixListener::UnixListener(const char *path, int mode)
+{
+  struct sockaddr_un addr;
+  mode_t saved_umask;
+  int err, result;
+
+  if (strlen(path) >= sizeof(addr.sun_path))
+    throw SocketException("socket path is too long", ENAMETOOLONG);
+
+  // - Create a socket
+  initSockets();
+  if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+    throw SocketException("unable to create listening socket", errno);
+
+  // - By default, close the socket on exec()
+  fcntl(fd, F_SETFD, FD_CLOEXEC);
+
+  // - Delete existing socket (ignore result)
+  unlink(path);
+
+  // - Attempt to bind to the requested path
+  memset(&addr, 0, sizeof(addr));
+  addr.sun_family = AF_UNIX;
+  strcpy(addr.sun_path, path);
+  saved_umask = umask(0777);
+  result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+  err = errno;
+  umask(saved_umask);
+  if (result < 0) {
+    close(fd);
+    throw SocketException("unable to bind listening socket", err);
+  }
+
+  // - Set socket mode
+  if (chmod(path, mode) < 0) {
+    err = errno;
+    close(fd);
+    throw SocketException("unable to set socket mode", err);
+  }
+
+  // - Set it to be a listening socket
+  if (listen(fd, 5) < 0) {
+    err = errno;
+    close(fd);
+    throw SocketException("unable to set socket to listening mode", err);
+  }
+}
+
+UnixListener::UnixListener(int sock)
+{
+  fd = sock;
+}
+
+UnixListener::~UnixListener()
+{
+  struct sockaddr_un addr;
+  socklen_t salen = sizeof(addr);
+
+  close(fd);
+
+  if (getsockname(getFd(), (struct sockaddr *)&addr, &salen) == 0)
+    unlink(addr.sun_path);
+}
+
+void UnixListener::shutdown()
+{
+  ::shutdown(getFd(), 2);
+}
+
+
+Socket*
+UnixListener::accept() {
+  int new_sock = -1;
+
+  // Accept an incoming connection
+  if ((new_sock = ::accept(fd, 0, 0)) < 0)
+    throw SocketException("unable to accept new connection", errno);
+
+  // - By default, close the socket on exec()
+  fcntl(new_sock, F_SETFD, FD_CLOEXEC);
+
+  // - Create the socket object
+  return new UnixSocket(new_sock);
+}
+
+int UnixListener::getMyPort() {
+  return 0;
+}

common/network/UnixSocket.h

@@ -0,0 +1,70 @@
+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright (c) 2012 University of Oslo.  All Rights Reserved.
+ * 
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+// -=- UnixSocket.h - base-class for UNIX stream sockets.
+//     This header also defines the UnixListener class, used
+//     to listen for incoming socket connections over UNIX
+//
+//     NB: Any file descriptors created by the UnixSocket or
+//     UnixListener classes are close-on-exec if the OS supports
+//     it.  UnixSockets initialised with a caller-supplied fd
+//     are NOT set to close-on-exec.
+
+#ifndef __NETWORK_UNIX_SOCKET_H__
+#define __NETWORK_UNIX_SOCKET_H__
+
+#include <network/Socket.h>
+
+namespace network {
+
+  class UnixSocket : public Socket {
+  public:
+    UnixSocket(int sock, bool close=true);
+    UnixSocket(const char *name);
+    virtual ~UnixSocket();
+
+    virtual int getMyPort();
+
+    virtual char* getPeerAddress();
+    virtual int getPeerPort();
+    virtual char* getPeerEndpoint();
+    virtual bool sameMachine();
+
+    virtual void shutdown();
+    virtual bool cork(bool enable);
+
+  private:
+    bool closeFd;
+  };
+
+  class UnixListener : public SocketListener {
+  public:
+    UnixListener(const char *listenaddr, int mode);
+    UnixListener(int sock);
+    virtual ~UnixListener();
+
+    virtual void shutdown();
+    virtual Socket* accept();
+
+    int getMyPort();
+  };
+
+}
+
+#endif // __NETWORK_UNIX_SOCKET_H__

unix/xserver/hw/vnc/Xvnc.man

@@ -91,6 +91,15 @@ Use IPv4 for incoming and outgoing connections. Default is on.
 Use IPv6 for incoming and outgoing connections. Default is on.
 .
 .TP
+.B \-rfbunixpath \fIpath\fP
+Specifies the path of a Unix domain socket on which Xvnc listens for
+connections from viewers, instead of listening on a TCP port.
+.
+.TP
+.B \-rfbunixmode \fImode\fP
+Specifies the mode of the Unix domain socket.  The default is 0600.
+.
+.TP
 .B \-rfbwait \fItime\fP, \-ClientWaitTimeMillis \fItime\fP
 Time in milliseconds to wait for a viewer which is blocking the server. This is
 necessary because the server is single-threaded and sometimes blocks until the

unix/xserver/hw/vnc/vncExtInit.cc

@@ -34,6 +34,7 @@
 #include <rfb/Region.h>
 #include <rfb/ledStates.h>
 #include <network/TcpSocket.h>
+#include <network/UnixSocket.h>
 
 #include "XserverDesktop.h"
 #include "vncExtInit.h"
@@ -79,6 +80,8 @@ rfb::IntParameter httpPort("httpPort", "TCP port to listen for HTTP",0);
 rfb::AliasParameter rfbwait("rfbwait", "Alias for ClientWaitTimeMillis",
                             &rfb::Server::clientWaitTimeMillis);
 rfb::IntParameter rfbport("rfbport", "TCP port to listen for RFB protocol",0);
+rfb::StringParameter rfbunixpath("rfbunixpath", "Unix socket to listen for RFB protocol", "");
+rfb::IntParameter rfbunixmode("rfbunixmode", "Unix socket access mode", 0600);
 rfb::StringParameter desktopName("desktop", "Name of VNC desktop","x11");
 rfb::BoolParameter localhostOnly("localhost",
                                  "Only allow connections from localhost",
@@ -181,6 +184,21 @@ void vncExtensionInit(void)
             listeners.push_back(new network::TcpListener(vncInetdSock));
             vlog.info("inetd wait");
           }
+        } else if (rfbunixpath.getValueStr()[0] != '\0') {
+          char path[PATH_MAX];
+          int mode = (int)rfbunixmode;
+
+          if (scr == 0)
+            strncpy(path, rfbunixpath, sizeof(path));
+          else
+            snprintf(path, sizeof(path), "%s.%d",
+                     rfbunixpath.getValueStr(), scr);
+          path[sizeof(path)-1] = '\0';
+
+          listeners.push_back(new network::UnixListener(path, mode));
+
+          vlog.info("Listening for VNC connections on %s (mode %04o)",
+                    path, mode);
         } else {
           const char *addr = interface;
           int port = rfbport;

vncviewer/CConn.cxx

@@ -39,6 +39,9 @@
 #include <rdr/MemInStream.h>
 #include <rdr/MemOutStream.h>
 #include <network/TcpSocket.h>
+#ifndef WIN32
+#include <network/UnixSocket.h>
+#endif
 
 #include <FL/Fl.H>
 #include <FL/fl_ask.H>
@@ -106,10 +109,19 @@ CConn::CConn(const char* vncServerName, network::Socket* socket=NULL)
 
   if(sock == NULL) {
     try {
-      getHostAndPort(vncServerName, &serverHost, &serverPort);
+#ifndef WIN32
+      if (strchr(vncServerName, '/') != NULL) {
+        sock = new network::UnixSocket(vncServerName);
+        serverHost = sock->getPeerAddress();
+        vlog.info(_("connected to socket %s"), serverHost);
+      } else
+#endif
+      {
+        getHostAndPort(vncServerName, &serverHost, &serverPort);
 
-      sock = new network::TcpSocket(serverHost, serverPort);
-      vlog.info(_("connected to host %s port %d"), serverHost, serverPort);
+        sock = new network::TcpSocket(serverHost, serverPort);
+        vlog.info(_("connected to host %s port %d"), serverHost, serverPort);
+      }
     } catch (rdr::Exception& e) {
       vlog.error("%s", e.str());
       if (alertOnFatalError)